Defroster for refrigerating systems



Jan. 21, '1941. F. T. LEILICH DEFROSTER FOR REFRIGERATING SYSTEMS Filed April 20, 19:57

2 Sheets-Sheet l ATTORNEY.

j g INVENTOR.

Jam 1941- F. T. LEILICH 2,229,181

' .DEFROSTER FOR REFRIGERATING SYSTEMS I Filed April 20, 1957 2 Sheets-Sheet 2 1M 7 f INVENTOR.

ATTORNEY.

Patented Jan. 21, 1941 r 2,229,181

STATES PATENT O F nsraos'raa Fort anmioansrm SYSTEMS Frank T. Leilich, Baltimore,- Md., assignor to James M. C. Speirs andlrvin Pool, both of Lansdale,l 'a. 1

Application April 20, 1937," Serial No. 137,945 1 Claim. (01. 62-4) Thisinvention relates to improvements in de- "unit; also on commercial refrigeration coils the frosters for refrigerating systems. brine refrigerant or other cooling medium may In the ordinary household refrigerators the beshutorf through operation of suitable valves cooling elements become covered with ice or frost or controls that would be caused to function by after the apparatus has been operated for varythe present mechanism. ing lengths of time; As this frost accumulates v It is understood that alarms, signals or other it forms a partial heat insulating covering and warning devices may be caused to operate in condecreases the cooling effectiveness of the re- Junction with the present equipment, either with frigerating unit. On the cooling coils of commeror without the present automatic control.

m cial or industrial units it is also for the same rea- With these and other objects in view, the ins0n objectionable to permit excessive ice or frost vention consists in certain novel features, comaccumulation on the refrigerating elements. bination and arrangement of parts as will be As the amount of frost that accumulates upon hereinafter more fully described, pointed out in the refrigerating elements depends upon the the accompanying drawings, and claimed.

a quantity and humidity of the air coming into In the accompanying drawings 1 have illuscontact with the cold surface, it is obvious that trated diagrammatically, my preferred form of time required for the same amount of accumulaautomatic defrosting device for refrigerating tion'of frost will vary widely. In a hot humid systems, the same embodying the various feaclimate the frost would form much more rapidly tures of my invention in their preferred form.

,20 than in a dry climate under the same conditions Figure 1 is a fragmentary view of a household of use of the refrigerating system. Therefore, type of refrigerating unit, illustrating the appliit is the purpose of the inventor to provide decation thereto of my frost control device. frosting means to correct this condition, that in Figure 2 is a diagrammatic view of my invenno way interferes with the normal operation of tlon, illustrating the defrosting gauge member the equipment, one which is rugged, simple, free and the actuating electrical circuit that controls 25 from changes in atmospheric or operating conthe stopping and starting of the refrigerating ditions, and without adjustments or attention by equipment. the operator, after being set for a predetermined Figure 3 is a view on an enlarged scale, which operating condition. a is similar to Figure 2.

An important object of the present invention Referring to the drawings by reference let- 30 is to provide means whereby an apparatus of ters, an. is the feeler or frost contacting gauge this class, consisting essentially of a timing dewhich is periodically moved towards the ice or vice, which maybe adjustable, comprising means frost covered surface 12, by the pull of alterwhereby at predetermined intervals causes an nating current in the electrical system, hereinice or frost thickness gauge to operate, which after described. A magnet d attracts armature 35 gauge, in the event the frost thickness equals e, which is mechanically linked to aa. The

or exceeds a predetermined thickness, is actuarmature e, is actuated by electric current passated and the refrigerating mechanism is shut ofi. ing through the circuit when cutout switch r is for a predetermined length of time, when the in closed position. A timing mechanism p, of the fiha s a n pe ordinary clock or electric type, drives the contact 40 A other O ject of the invention is to provide carrying disc 0 for purposes of electric circuits means whereby th foregoing op rati n may e shown through contacts 0 and 0" at predeterrepeated for each instance where the frost thickmined time intervals. It is understood that p ness reaches that for which the apparatus is set. may be replaced by other suitable timing mech- Obviously, with such a device, climatic changes anisms. Closing of the circuit through the con- 45 are automatically taken care of, as the cold is tacts o' and 0" causes a current to flow in the shut off when the ice accumulates to a certain magnets d and h connected, as shown, in'series thickness on the refrigerating unit or coils. and also through magnet i. The winding of A still further object of the invention is to coil h is such as to have a normally stronger provide means broadly applicable to automatimagnetic pull than magnet 2'. Thus upon the 50 cally defrost not only household equipment of the feeler or gauge aa touching b. the current present type but also in the use of a gas refrigthrough d and h is such that with no ice on b erator to function to act as auxiliary means to the pull of magnet i is stronger at that time beshut oil the gas and other connections that may cause of the additional choking action of the 5 be necessary to the operation of this type of armature e in contact with both pole pieces of magnet d, that is, reducing the airgap in the magnetic field circuit of magnet d. The current passing through the coil circuit of magnet d, is reduced as the air gap in the magnetic circuit of magnet d is reduced, but the current through coil 1 is always the same. The pivoted armature 7' is pulled down toward the magnet i, which action through arm is and the pin members l' and 1" throws the toggle controlled element 1 to such a position that the mercury switch m closes the circuit 12 through contacts n controlling the operation of the driving motor of the refrigerating system. If accumulated ice or frost holds the feeler off of b a sufllcient amount of time, the armature e will not approach close enough to member d to reduce the current flowing in magnets d and h sufficiently to enable the pull of magnet i to overcome the pull of h and the toggle will be tripped causing the mercury switch to open the refrigerating motor cir cuit n. A spring 0 is provided to return the feeler a to the open position, so that the normal rate of formation of frost on b is not interfered with. This feeler or gauge a. is adjustable through its threaded end a for causing the same to operate the control mechanism for a predetermined thickness of frost on the refrigerating unit b.

I have thus described my invention in detail in order that'its operation and structure may be fully understood; however, the terms'herein are used in their descriptive sense only and not in a limited manner. The scope of the invention being defined in the claim, wherein it is understood that this invention is not to be limited wholly to an apparatus but also to a system as well for automatically controlling the defrosting of refrigerating apparatus, units and systems.

Having fully-described myinvention, what I claim as new is:

A defrosting device for refrigerating systems including a refrigeration circuit comprising the evaporator, compressor, motor and motor control switch, a refrigerating element, an electrical magnet associated with said element, a feeler movable towards and away from said refrigerating element and controlled by said electrical magnet, an electrically operated means to con-- trol the magnet and feeler at predetermined intervals to move the feeler towards and away from the refrigerating element so that the defrosting action of the refrigerating element may be made at predetermined intervals by the electrically controlled device, all of said elements being in the refrigeration circuit.

FRANK I. LEILICH. 

